Pd(OAc)2-Catalyzed Macrocyclization of 1,2-Diazonaphthoquinones with Cyclic Ethers
摘要:
Pd(OAc)(2) was found to be an efficient catalyst for the macrocyclization of 1,2-diazonaphthoquinones and cyclic ethers. This transformation serves as an efficient method for the synthesis of protected 1,2-naphthalenediols.
Various orthodiazonaphthoquinones (1-diazo-2(1H)-naphthalenones and 2-diazo-1(2H)-naphthalenones) were synthesized using the diazo-transfer reaction between the appropriate naphthol and 2-azido-1,3-dimethylimidazolinium chloride (ADMC). The ADMC was prepared by the reaction between 2-chloro-1,3-dimethylimidazolinium chloride and sodium azide. The diazo-transfer reaction selectively introduced the diazo group at the C(2) position of 1-naphthol or the C(1) position of 2-naphthol. The naphthalenediols that were tested, except for 1,3-naphthalenediol, also reacted with ADMC to afford the corresponding monodiazotized compound. X-ray analyses suggested that the diazonaphthoquinones did not have diazoniumnaphtholate structures but had diazocarbonyl structures.